The editors of the New England Journal of Medicine, in a rare move, said that it is too soon to dismiss concerns about cancer risks linked to the popular cholesterol drug Vytorin, even as the journal published a report saying a previously reported cancer link was likely due to chance.

The NEJM's editorial was formally released just as experts were defending the drug's safety at a major medical conference in Europe. A study formally presented Tuesday, known as SEAS, raised questions about potential cancer links, and whether Vytorin helps prevent cardiovascular problems better than a placebo. Those conclusions were made public in July. But a prominent Oxford University researcher said the cancer risk wasn't credible. The New England Journal published both the SEAS study and the Oxford review of the cancer issue.

Later Tuesday, a powerful congressional committee that has been investigating Vytorin's safety and marketing sent a letter to Merck & Co. and Schering-Plough Corp., who sell the drug in a joint venture, asking for extensive details about the Oxford review that dismissed links between Vytorin and cancer deaths.